<template>
    <div class="mb">
        
    </div>
</template>

<style lang="less" scoped>
body{
    position: relative;
}
.mb{
    width:100%;
    height: 100%;
    background-color: rgb(138, 138, 138);
    opacity: 0.2;
    position: absolute;
    top: 0;
    z-index:0;
}
</style>